package 题目集.二分;

import java.util.Scanner;

public class ch11_转换率 {
    static int n;
    static double k;
    static long[] arr;

    static long p = (long) 1e8;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        k = sc.nextLong();
        k = 1 - k / 100;
        arr = new long[n];
        long l = Long.MAX_VALUE, r = Long.MIN_VALUE;
        for (int i = 0; i < arr.length; i++) {
            arr[i] = sc.nextLong() * p;
            l = Math.min(l, arr[i]);
            r = Math.max(r, arr[i]);
        }
        long l1 = find(l, r);
        System.out.printf("%.9f", 1.0 * l1 / p);
    }

    public static long find(long l, long r) {
        while (l <= r) {
            long m = l + (r - l >> 1);
            if (check(m)) {
                l = m + 1;
            } else {
                r = m - 1;
            }
        }
        if (check(l)) {
            return l;
        }
        return r;
    }

    /**
     * 每个人m能里昂是否能分
     */
    public static boolean check(long m) {
        long ans = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] < m) {
                ans -= m - arr[i];
            } else {
                ans += (long) ((arr[i] - m) * k);
            }
        }
        return ans >= 0;
    }
}
